Improvement in elevators



w". A. Munnlsow.

Elevators. No., 137,789. ParentedApm15,187s.

UNITED STATES PATENT OFFICE.

WILLIAM A. MORRISON, OF CAMBRIDGE, MASSACHUSETTS.

IMPROVEMENT IN ELEVATORS.

Specification forming part of Letters Patent No. 137,789, dated April` l5, 1873; application filed March 6, 1873.

To all whom, t may concern:

Be it known that I, WILLIAM A. MORRISON, of Cambridge, of the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Elevators and do hereby declare the same to be fully described in the following specification and represented in the accompanying drawing, of which- Figure l is a top view, Figs. 2, 3, and 4 vertical sections, and Fig. 5 a front elevation, of a goods-elevator provided with my invention, the purpose of which is to arrest the descent of the elevator in case of accidental breakage of the chain or rope used for raising it.

In the drawing, A denotes an elevator arranged between vertical guides B B, each of which on its inner side has a tongue, O, projecting from it in manner as shown. Aftixed upon the extremities of two horizontal shafts, D D, arranged within the upper part of the elevator in manner as represented, are eccentrics E E, which are disposed on opposite sides of one of the tongues, there being two such eccentrics to each tongue. At its inner end each of the shafts has a crank or arm, F, eX- tended from it, such cranks being arranged as shown, and pivoted to the outer ends of a curved cross-head or bar, G, to which, by means of a rod, H, or other suitable device, the lifting rope or chain of the elevator is to be fastened. A lever, I, pivoted at its inner end to the cross-head, and arranged within, and having its fulcrum supported by, the elevator, has attached to its longer arm the line -K of the balance-weight W of the elevator.

The upper part of the lifter-rod H is furcated to receive a lever, L, which at its middle is placedwithin and pivoted to the said rod. At its opposite ends the lever has eyes a a for the purpose of attaching to it two separate lifting chains or ropes.

In case of breakage of either rope the other lever will drop into a vertical position and hold up the elevator.

The lever is to equalize the strains on the two ropes, in order that one of them may not be unduly weighted. It is important that the lever, on breakage of a rope, should drop vertically, in order that the rope may not be subjected to oblique strain or the `platform be tipped to cause it to jam in the guides or tongues.

From the above it will be seen that, while the elevator may be supported by its lifting rope or chain, the eccentrics will be maintained out of action upon the tongues of the guides; but, should the rope or chain become broken, the cross-head will drop or be drawn downward so as to pull down the cranks, and thereby cause the shafts to be revolved in a manner to force the eccentrics hard against the tongues, and thereby arrest the descent of the elevator. The counterbalance-Weight, being connected by the lever with the cross-head, will contribute to depress or aid in depressing the cross-head.

I would remark that, instead of four shafts and four cranks, two shafts to extend entirely across the elevator and having two cranks may be substituted; but I prefer the four shafts and four cranks.

I claim- The eccentrics E, the shafts D, cranks F, and cross-head G, arranged together and applied to the lifter-rope, or its rod, of the elevator, and to the vertical tongues ofthe guides,

substantially in manner and to operate as set forth, in combination with the lever I, balanceweight W, and line K, arranged and combined, as set forth, with the elevator lifting rope or chain or rod H thereof, all being as, :and to operate essentially as, specified.

yWitnesses: WM. A. MORRISON.

R. H. EDDY, J. R. SNow. 

